Under certain operating conditions aircraft are vulnerable to accumulation of ice on component surfaces. It is well known that such accumulation of ice can lead to disastrous results. A wide variety of systems have been developed for removing ice from aircraft during flight and can be placed into three general categories: thermal, chemical, and mechanical.
The mechanical category of deicing systems operate by distorting the airfoil surface of the aircraft to be deiced. Distortion of the airfoil surface causes cracking in the ice accumulated thereon, and subsequent dispersal of that ice into the air stream passing over the aircraft component.
The principal commercial mechanical deicing means is commonly referred to as pneumatic deicing wherein a component (e.g. the leading edge of a wing) of an aircraft is covered with a plurality of expandable, generally tube-like structures inflatable by employing a pressurized fluid, typically air. Upon inflation, the tubular structures tend to expand substantially the leading edge profile of the wing or strut and crack ice accumulating thereon for dispersal into the air stream passing over the aircraft component. Typically, such tube-like structures have been placed on the leading edge of the aircraft component and configured to extend substantially parallel to said leading edge. The typical inflation time for such pneumatic deicers is between 3 to 6 seconds. The typical air pressure used to inflate the tube-like structures is below 22 psi.
A problem with such leading edge pneumatic deicers, however, is that under certain conditions a buildup of ice occurs on airfoil surfaces chordwise aft of deicer. The thickness of such ice which can be tolerated in this area depends on the airfoil, with some airfoils being extremely sensitive to the presence of such ice. The availability of additional air or energy to deice this increased area, however, may be limited or unavailable.
U.S. Pat. No. 5,112,011 discloses a pneumatic deicer for shedding thin ice which utilizes very high pressure and very small inflated tube radius, the disclosure of which is hereby fully incorporated herein by reference. Such high pressures are not typically available for pneumatic systems, and are impractical because they are too destructive to the pneumatic deicer materials.
Efforts to improve such systems have led to continuing developments to improve their versatility, practicality and efficiency.